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Published byRosalind York Modified over 9 years ago
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Two types of matter: Mixtures Pure substances
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Mixtures: Consists of two or more substances that are mixed together but not chemically combined Ex: pre-baked cookies Solution – liquid mixture Soda; sea water 2 types of mixtures Homogeneous – uniform composition Heterogeneous – not uniform composition
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Pure Substances Is made of only one kind of matter and has definite properties. Ex: sugar, salt, gold, iron Elements – are pure substances that cannot be broken down anymore. Look at periodic table Compounds – is a pure substance formed from chemically combining two or more different elements H2O, CO2, C6H12O6 Atoms – smallest particle of a element
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States of Matter Notes A sheet of paper is about 10,000 atoms thick. There are 2000 billion billion atoms of oxygen in one drop of water (double that for hydrogen)! A sheet of paper is about 10,000 atoms thick. There are 2000 billion billion atoms of oxygen in one drop of water (double that for hydrogen)!
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Atoms are held together by a chemical bond. A molecule is a group of atoms that are joined together and act as a single unit. For example, H 2 O is made up of 2 hydrogen atoms and 1 oxygen atom and is VERY different from hydrogen alone or oxygen alone. There are 3 atoms in one molecule of water.
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Pure Substances
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4 states of matter: Solids Liquids Gasses
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4th State of Matter is Plasma. Just be aware of it…
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Solids: have a definite volume and a definite shape. will keep that volume and shape in any position and in any container. Particles in a solid are packed very tightly together and stay in fixed positions. These particles do move back and forth slightly—like balls connected by tight springs.
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Crystalline solids-- particles form regular, repeating patterns. e.g. salt, sugar, sand. Amorphous solids—no pattern to particles. e.g. Butter, glass, plastic, rubber.
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Liquids: have no shape of their own, but do have a definite volume. takes shape of container. Particles in a liquid are packed tightly together but they move around each other freely.
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Viscosity: - the resistance of a liquid to flowing. More viscous = more “thick”.
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Gases: have no definite shape or volume. can change volume easily. Particles in a gas fly at high speeds in all directions, filling all the space available to them. They can be spread out to “fill” any space or they can compact together in a smaller space.
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Draw this
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Characteristics Properties Properties for a given substance that never change. (always remain the same) water freezes at 32 degrees boils at 212 Physical Changes – alter the form of a substance Boiling Point Melting point Chemical Changes – one or more substances combine or break apart to form new substance Wood being burnt. Burning in general
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